thermostat cable insulation voltage rating

I've noticed that in many/most modern furnaces the thermostat cable enters and connects to the control module in the same compartment with various line-voltage wiring. In fact, much of the line-voltage wiring terminates on the same control module. There is no partition to keep the low-voltage and line-voltage wiring separate. This would seem to violate the frequently quoted rule about separation of low- and line- voltage wiring unless thermostat cable insulation is supposed to be rated for line voltage. The thermostat cable I've seen is CL2 with a 105C temperature rating but says nothing special about voltage. Is it 300V or 600V rated?
                Dan Lanciani                 ddl@danlan.*com
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Manufactures get to do what ever they want when the designs are submitted to the testing agencies like UL and CSA. I worked for an electrical manufacture that ran line and low voltage in the same bundle ty-wrapped together. As long as you see the acceptance sticker on it chalk it up to the way of the world.
Check out a electric waterheater. Fed with a minimum of #10 and inside the manufactures use #12.
Air conditioner condensers are the same situation
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SQLit wrote:

Practices which wouldn't be permitted by NEC are routinely OK'd *inside* the appliance where UL feels the mfr has sufficient control to satisfy some minimal level of safety.
Jim
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